cometarium
Datecirca 1766
Inventory Number0006
ClassificationCometarium
Subject
Maker
Benjamin Martin
1704 - 1782
Cultural Region
Place of Origin
Place of Use
Dimensions5.5 x 18 x 30 cm (2 3/16 x 7 1/16 x 11 13/16 in.)
Material
Bibliography
DescriptionA mahogany box with lock and key contains inside a gear and cam drive mechanism. A three-part brass plate, made of a circle encompassed within and oval itself encompassed within the rectangular boundaries of the instrument, is fastened to the wooden lid of the box. The mechanism, operated by a hand-crank (missing), turns two brass pointers. The longer one pushes a brass ball along an elliptical orbit. The other pointer measures time on a scale marked off in yearly units from 1 to 75 1/2.
In one of Benjamin Martin's price list catalogues, he mentions: "Cometarium, 5 [l.] 5 [s.]"
In one of Benjamin Martin's price list catalogues, he mentions: "Cometarium, 5 [l.] 5 [s.]"
In Collection(s)
Signedon brass plate: A COMETARIUM / B Martin London
Inscribedon ivory key tag: Cometarium (in script)
FunctionThis apparatus was designed to demonstrate how the speed of a comet varies in its orbit according to Kepler's law of equal areas. The comet Benjamin Martin chose for this instrument is Halley's Comet, which goes around the Sun every 75 1/2 years. Martin began producing cometaria before Halley's Comet made its predicted return, and so was betting that Halley would prove correct in his theory.
ProvenanceJefferson Physical Laboratory, Harvard University; transferred to CHSI May 1948.
Historical AttributesWhen Halley's comet reappeared on schedule in 1759, it aroused keen interest throughout Europe, America, and apparently at Harvard too. According to Wheatland's book, "A Cometarium worth £3.13.6 was one of the first instruments that the College ordered in 1766 to restock its new philosophical chamber" after the fire of 1764.
Arnheiter
Date: 1830-1840
Accessories: magnets (2); wooden handle with hook; case
Object number: DW0899
James W. Queen & Company
Date: circa 1890
Object number: 1906
Louis François Dellebarre
Date: 1775-1795
Accessories: Lieberkühn; cap for ocular; no case.
Object number: 1255
Blue Hill Meteorological Observatory
Date: 1895-1919
Accessories: Panorama of landmarks visible from the Blue Hill Meteorological Observatory
Map of the Blue Hills Reservation and its surrounding area from 1919
Topographical map of the Blue Hills Reservation from 1895
Object number: 1998-1-0977
International Meteorological Organization
Date: dated 1894
Accessories: matte board
Object number: 1998-1-1075